Fraser Nelson is dead right about the threat to free speech posed by any kind of state regulation. It would begin with promises of a light touch and as a result of the inevitable mission creep, end up as a suffocating restraint.

He also mentioned that in happy anticipation of Leveson, politicians have been making unprecedented complaints to him about journalists who’ve annoyed them. I’m familiar with that world. During the long-drawn-out Irish peace process, the few journalists who were critical of appeasement found it difficult to get published in any southern newspapers other than those controlled by Sir Anthony O’Reilly, who believed in standing up to terrorism. His newspaper showed rare courage.

“Have you any idea,” he asked me once in a rare meeting, “what pressure I’ve been under to stop you writing in the Sunday Independent?” I hadn’t known it was so bad: I would later discover also that those cheery freedom fighters – Gerry Adams and Martin McGuinness – had enquired of officialdom how I could be shut up. Fortunately, there was no state regulation, but libel laws more restrictive even than those of the UK were employed ruthlessly by republicans to enrich them and terrify newspaper managements. What was even more sinister was that politicians and officials made it privately clear that any commentator criticising government policy on Northern Ireland was considered unpatriotic and anti-peace and would be frozen out.

A decade later, just before the Celtic Tiger had a heart attack, Bertie Ahern remarked apropos the few economists suggesting there were problems brewing. “Sitting on the sidelines, cribbing and moaning is a lost opportunity. I don't know how people who engage in that don't commit suicide”. He later apologised, not for discouraging free speech, but because he was accused of being insensitive about suicide.

British politicians are far more robust. They have had to be because of the noble British tradition of thumbing noses at our so-called betters. They’ve often put up with dreadful unfairness and we all know plenty about press excesses. But, like their Irish equivalents, they would much prefer a quiescent press. And if they have the means to quiet it, that’s what they’ll do. It’s human nature.

There’s another danger to a free press, though, and that’s self-censorship. There’s the “you-can’t-say-that!” cadres who suggest your views are too offensive to express, or that you should write only for papers of which they approve. I’ve been very fed-up at times when told by bien pensants that they couldn’t understand why I would write for such vulgar, aggressive rags as the Sunday Independent and the Daily Mail. The answer was that they allowed me to express views unacceptable among the right-on and I honour them for it.

There are few UK journalists demanding to have the kind of free-for-all enjoyed by irresponsible US organs, but the mainstream American media suffer from the terrible scourge of self-censorship. I’m not a fan of Fox News, but there’s a need to challenge the dominance of a bland, smug, self-consciously “responsible” media which mostly peddles uncritically the line of the liberal intelligentsia. Their failure – even as they took the microscope to Sarah Palin – to poke around the discreditable aspects of Barack Obama’s record and the dodgy past of many of his Chicago circle, was shocking.

As a crime novelist, I set out to write murder stories and found myself writing satires. I have a reactionary, tactless but life-enhancing heroine, Ida “Jack” Troutbeck, who though the Mistress of a Cambridge college is savage about much of academia, and who as a peer and pundit takes on the liberal establishment at every turn. Her latest target, about which I’ll write next week, is an art establishment that extols the “pretentious, specious, nihilistic” rubbish known as conceptual art. “You can’t say that about Nicholas Serota!” said one friend who read the typescript and panicked that he was described as a “bloody nincompoop”. “I’m not saying it,” I pointed out. “Baroness Troutbeck is. But I consider her opinion valid.”

No one should trash another’s reputation without good reason. I’m delighted Lord McAlpine is bringing that truth home to the thoughtless as well as the malign. But we must resist the self-censorship that comes from group think. And even more, we must fight to the end to stop the state getting any kind of legal control over the press.